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Old 17-09-2018, 01:44 AM
Granada
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Eyepiece suggestions

Soon I'll be taking delivery of a Celestron Nexstar 6SE (FL 1500mm, A 150mm) and I was hoping for some suggestions on a good quality eyepiece to match it with. I already have two cheap Plossls (10 & 25mm), 9mm Nagler 6, 31mm Nagler 5, and Tele Vue Barlow (x2).


Does that sound like a good enough set to view the planets in the solar system (with the 9mm Nagler) and deep sky objects (with 31mm Nagler), or should I add one more eyepiece to my collection? I'm keen on Tele Vue

Last edited by Granada; 17-09-2018 at 09:38 AM.
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Old 17-09-2018, 01:02 PM
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Merlin66 (Ken)
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You have the main bases covered.
A 15mm would be a good mid range choice.
One of the wide field options might be worth checking out.
You don’t need excellent eyepieces with an f10 system; I was told when I started out than even the bottom of a coke bottle would work well at f10!!
Never did try it......
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Old 17-09-2018, 01:10 PM
Granada
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Thanks Ken. Just out of curiosity, why do you say "You don’t need excellent eyepieces with an f10 system"?
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Old 17-09-2018, 01:28 PM
Chapstick (Jared)
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I had the 6SE and my most used EP's were 13 & 32mm (plossl) for most things. I found that on most nights planets looked better using the 13 compared to the 8 which I was only able to use on nights of excellent seeing.

Slower scopes like this are not as demanding on eyepieces as faster systems like are often used in newtonian reflectors which are more prone to aberations when using lesser quality EP's.

The logical buy would be something in the 15-17mm range but I would wait until you use the scope and see if it is required..

BTW the visual back on the 6SE only supports 1.25" EP's
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Old 17-09-2018, 01:35 PM
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Merlin66 (Ken)
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The narrow light cone associated with slow systems, >f8 puts less demands on the eyepiece optics. Less eyepiece elements and less curved surfaces are required to give aberration free, well almost, performance.
Faster optics <f5 put far more onus on the eyepiece to be able to cope with the very steep light cone. This requires more complex glass shapes, spacing and usually more elements to give acceptable performance.
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Old 17-09-2018, 03:27 PM
ausastronomer (John Bambury)
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Quote:
Originally Posted by Merlin66 View Post
The narrow light cone associated with slow systems, >f8 puts less demands on the eyepiece optics. Less eyepiece elements and less curved surfaces are required to give aberration free, well almost, performance.
Faster optics <f5 put far more onus on the eyepiece to be able to cope with the very steep light cone. This requires more complex glass shapes, spacing and usually more elements to give acceptable performance.
Hi Ken,

That's true only to a certain extent. The shallower light cone certainly is a lot more forgiving for cheaper eyepieces and will enable cheaper eyepieces to work reasonably well in that system. On that basis a lot of aberrations from the eyepiece itself are eliminated. So its only the inherent telescope aberrations that come into play

It's worth remembering however that some of the telescope aberrations are inherent on the radius of curvature of the primary optic. For instance SCT's have a lot of field curvature because it is a function of the ROC of the primary optic which with most SCT's is fast at F2 to F3. This is the reason most imagers use a field flattener when imaging with an SCT.

The point of my post is that you can't make an overall assumption that because the overall F Ratio of the telescope is slow at F10, that it will essentially be aberration free.

You can make a reasonable assumption that cheap eyepieces will generally work better in an F10 SCT, than they will in an F5 Newtonian, but they may still be a long way from aberration free.

Cheers
John B
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Old 17-09-2018, 03:32 PM
Granada
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BTW the visual back on the 6SE only supports 1.25" EP's

Ahh good point, means I won't be able to use my 31mm Nagler 5 with it. I assume there's something you can purchase to adapt a 2" EP to a 1.25" barrel?
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Old 17-09-2018, 03:39 PM
ausastronomer (John Bambury)
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Quote:
Originally Posted by Granada View Post
Soon I'll be taking delivery of a Celestron Nexstar 6SE (FL 1500mm, A 150mm) and I was hoping for some suggestions on a good quality eyepiece to match it with. I already have two cheap Plossls (10 & 25mm), 9mm Nagler 6, 31mm Nagler 5, and Tele Vue Barlow (x2).


Does that sound like a good enough set to view the planets in the solar system (with the 9mm Nagler) and deep sky objects (with 31mm Nagler), or should I add one more eyepiece to my collection? I'm keen on Tele Vue
Hi,

The 31mm Nagler is a great eyepiece but it is likely it will not work well at all in that telescope. The 31mm Nagler is a 2" eyepiece with a 42mm field stop. Even if you upgraded to a 2" diagonal so that it physically fit into the telescope, it is very likely that the narrow baffle tube on the 6SE will vignette and narrow the FOV. I may be wrong, but just trying to give you a heads up before you race out and burn money on a 2" diagonal!

Cheers
John B
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Old 17-09-2018, 03:44 PM
Granada
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Originally Posted by ausastronomer View Post
Hi,

The 31mm Nagler is a great eyepiece but it is likely it will not work well at all in that telescope. The 31mm Nagler is a 2" eyepiece with a 42mm field stop. Even if you upgraded to a 2" diagonal so that it physically fit into the telescope, it is very likely that the narrow baffle tube on the 6SE will vignette and narrow the FOV. I may be wrong, but just trying to give you a heads up before you race out and burn money on a 2" diagonal!

Cheers
John B

Thanks John,


So if I were to take the 31mm Nagler out of the picture, what would be a good EP to purchase in addition to the 3 others I already have + a Barlow?


I used Tele Vue's calculator to find suitable EPs, and have had my eye on the Ethos 13mm - but it's quite expensive. If I'm going to invest in such an excy EP, I want to make sure it's appropriate for what I'm going to use it for.


I should also mention that although I'm going to be using these EPs with the SCT, I'm making more of an investment for the future so that I can use these same EPs with other scopes - hence why I'm eyeing (pun intended) the good quality ones.
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Old 17-09-2018, 04:06 PM
ausastronomer (John Bambury)
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Originally Posted by Granada View Post
Thanks John,


So if I were to take the 31mm Nagler out of the picture, what would be a good EP to purchase in addition to the 3 others I already have + a Barlow?

The 24mm Panoptic is a great eyepiece that will work well in that scope. It has a 1.25" barrel and gives 62X. It would see a lot of use as a medium power eyepiece.

You might also want to consider a 35mm Plossl type eyepiece. It won't give you much extra TFOV over the 24mm Panoptic but it will drop the power down to 42X and this will have "some" open clusters looking aesthetically a little nicer, as they will be a bit more compressed and not appear so fragmented as they do at higher power. One of the 5 element plossls 2nd hand might be the go. Orion Ultrascopic, Celestron Ultima, Antares Elite, Parkes Gold Series. They are basically the same eyepiece with different writing and if you can locate one you should get it for ~ $100 second hand. These are a high quality Japanese made eyepiece.

Cheers
John B
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Old 17-09-2018, 04:12 PM
ausastronomer (John Bambury)
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Originally Posted by Granada View Post
Thanks John,

I should also mention that although I'm going to be using these EPs with the SCT, I'm making more of an investment for the future so that I can use these same EPs with other scopes - hence why I'm eyeing (pun intended) the good quality ones.
That's always a good strategy. Aside from the optical benefits, the good ones hold their value pretty well and if you ever want to change them over at any time you will always have a decent resale value and be able to get most of your money back.

Cheers
John B
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Old 05-01-2019, 09:40 PM
Fleegal (Tony)
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I have just bought my 4th starguider eyepiece. Cheap but not because of quality, exceptional value. I use mine with 16" f4.5 and my 90mm f10 refractor without any problem at all. Good luck!
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Old 06-01-2019, 07:00 PM
TareqPhoto (Tareq)
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Good that i didn't start another thread about an eyepiece here, i did that in another place and ended up with 4 pages of discussions and points and still i didn't decide anything yet, so i will watch your thread who it will end up and what you will decide, good you already have TV eyepieces, my thread was about which TV i must have as i have NONE and i don't want to go for any less, but i feel people think i only want very expensive things no matter what, so you got the idea now.
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Old 06-01-2019, 07:06 PM
Granada
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I settled for the 32mm and 24mm panoptic and have not looked back. They both provide crisp, pinpoint views of the stars in my SCT. Orion nebula looks great too! Have not had a chance yet to test them on planets but I'm sure I won't be disappointed. Thanks everyone for your valuable advice.
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Old 07-01-2019, 02:12 PM
GAL1LEO
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Quote:
Originally Posted by Granada View Post
I settled for the 32mm and 24mm panoptic and have not looked back. They both provide crisp, pinpoint views of the stars in my SCT. Orion nebula looks great too! Have not had a chance yet to test them on planets but I'm sure I won't be disappointed. Thanks everyone for your valuable advice.
The 24mm Panoptic is a ripper. Highly recommend
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Old 07-01-2019, 04:48 PM
Startrek (Martin)
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I invested a lot of money in Televue Delos , Ethos and Panoptic eye pieces and have no regrets at all . Superb quality eye pieces, a lifetime investment.
The 24mm and 27mm Panoptic are brilliant eye pieces for glob and open clusters and Nebula, wide field , good contrast and colour and tac sharp to edge of field
I have used them in 6” , 10” and 12” f5 and f6 newts
Uncle Al is a legend !!
👍👍
Cheers
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Old 07-01-2019, 04:57 PM
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JeniSkunk (Jenifur)
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Martin, what diameter eyepiece mount was the F5 Newt you used? 2in or 1.25in?
I'd like to eventually get some TV eyepieces, but I'm not certain how effective they'd be on my Sky Watcher Heritage 130p, 130mm F5 Newt with a 1.25in eyepiece mount.
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Old 07-01-2019, 06:37 PM
Startrek (Martin)
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Jeni
All my scopes have dual speed 2” Crayford focusers which accept both 1.25 and 2” eye pieces
Cheers
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Old 07-01-2019, 07:20 PM
astro744
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One of the most versatile eyepieces and one of high quality is the Tele Vue 24mm Panoptic. Being 1.25" it can be used on telescopes with 1.25" only or 2" with 1.25" adapter. It has the largest field stop diameter possible in a 1.25" barrel (same as 32mm and 40mm Plossl). It has a nice 68 deg. apparent field unlike the 32mm Plossl (50 deg.) and 40mm Plossl (43 deg.). It gives a good not too large exit pupil at f5. It binoviews very well (provided your binoviewer also has 27mm clear aperture). It performs very well on any telescope design as it is highly corrected. It has comfortable eye relief of 15mm.

It is a highly recommended eyepiece. Enjoy!
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Old 07-01-2019, 10:55 PM
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All my scopes have dual speed 2” Crayford focusers which accept both 1.25 and 2” eye pieces
The focuser on my scope is rather more primitive, a helical focuser.
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